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A131712
Period 4: repeat [1, 3, 7, 9].
3
1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1
OFFSET
0,2
COMMENTS
Decimal expansion of 1379/9999. - Klaus Brockhaus, May 21 2010
FORMULA
G.f.: (1+3*x+7*x^2+9*x^3)/((1-x)*(x+1)*(1+x^2)). - R. J. Mathar, Nov 14 2007
From Wesley Ivan Hurt, Jul 09 2016: (Start)
a(n) = a(n-4) for n>3.
a(n) = 5 - 3*cos(n*Pi/2) - cos(n*Pi) - 3*sin(n*Pi/2) - I*sin(n*Pi). (End)
MAPLE
seq(op([1, 3, 7, 9]), n=0..40); # Wesley Ivan Hurt, Jul 09 2016
MATHEMATICA
PadRight[{}, 100, {1, 3, 7, 9}] (* Wesley Ivan Hurt, Jul 09 2016 *)
PROG
(PARI) a(n)=1+2*(n%4)+2*(n%4\2) \\ Jaume Oliver Lafont, Aug 28 2009
(Magma) &cat[[1, 3, 7, 9]: k in [1..30]]; // Vincenzo Librandi, Nov 23 2010
CROSSREFS
Cf. A178148 (decimal expansion of (243+17*sqrt(285))/402). - Klaus Brockhaus, May 21 2010
Sequence in context: A244338 A336045 A090458 * A072845 A197481 A197682
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Sep 14 2007
EXTENSIONS
More terms from Klaus Brockhaus, May 21 2010
STATUS
approved